Composition mortar for plastering walls
Any mixture for plastering walls should consist of: water, astringent components( cement, clay, gypsum, lime) and aggregates( slag, sawdust, sand, chips).In the case where there are no aggregates, some binding components can not provide the necessary strength. Select the ingredients( aggregates and binders), depending on the type of surface.
All components must be previously sieved. Clay and lime are brought to a creamy state. At the same time, water in the mixture has a big role. It provides high plasticity, excellent solidification and setting of the material. Depending on the consistency, all solutions can be "lean" and "fatty".
"Oily" and "skinny" plaster, which is better?
"Fat" means that there is more astringent ingredient in the mixture than is necessary. As a result, the material for the plastering of the walls is of poor quality, and the coating quickly cracked. In these cracks begins to get moisture, which leads to the final destruction of the material.
"Skinny" means a small amount of astringent ingredient( for example, lime).As a result, plasters provide a rather weak and unreliable coating. They also do not adhere well to the substrate and give poor adhesion for the subsequent application of paint or wallpaper.
For quality finishes, it is better to choose a mixture of medium density. Not "fat" and not "skinny".
How to prepare mortar for plaster?
Depending on the type of composition, the method of preparation is also different. For different mixtures it is necessary to maintain certain proportions and rules of preparation. About how to make a solution for plaster, we will tell below.
- The lime mixture is made in the ratio 1: 1-5, where 1 - slaked lime, 1-5 sand. The lime is placed in a container and 1 part of sand and water is added. The composition is thoroughly mixed until liquid( no lumps).Then add more sand until the plaster does not turn out medium density and again as follows to mix.
- Cement mortar is made of a cement grade not exceeding 400 and 1.5-5 parts sand. At the initial stage, a certain amount of sand is put in the container, and then a funnel is made from it, into which cement is poured. Next, the ingredients are thoroughly mixed and only then add the water in small portions.
- Cement-lime mixture is made in the ratio 1: 1.5: 0.3-1.5, where 1 is cement, 1.5 sand, 0.3-1.5 hydrated lime. The sand is mixed with cement, and then water is added to the liquid state. After pour lime milk.
- Lime-clay material is made in a ratio of 3-6: 0.4: 1( sand, hydrated lime, clay, diluted in water).First, stir slaked lime and clay, and then add the sand.
- Lime-plaster composition contains 1: 3-4( gypsum and hydrated lime).First poured into the container water, then add gypsum and then lime dough. All components are properly mixed until a viscous mass is obtained.
- The clay mixture , which has a low level of strength. When the question arises: how to build plaster from clay, then complications do not arise, since this is the main component. Sometimes there is added such material as cement, lime or gypsum.
After the recipes described above, there should not be a question - how correctly to make plaster. The only and always important point is that before applying any mixture you need to prepare the surface. To do this, it is important to remove the old plaster and pick up the main mixture, and then the textured plaster.
By the way, for interior finishing it is better to choose cement, gypsum or lime composition. Each of them is selected depending on the base.